当debug设置为false时，出现服务器错误（500），但是当debug = True时，站点运行正常
这是Heroku日志：[编辑：更改DJANGO日志后的新日志文件]
2017-07-30T17:19:06.000000+00:00 app[api]: Build succeeded
2017-07-30T17:19:25.874517+00:00 heroku[web.1]: State changed from up to starting
2017-07-30T17:19:25.873834+00:00 heroku[web.1]: Restarting
2017-07-30T17:19:26.809034+00:00 heroku[web.1]: Stopping all processes with SIGTERM
2017-07-30T17:19:26.828322+00:00 app[web.1]: [2017-07-30 17:19:26 +0000] [11] [INFO] Worker exiting (pid: 11)
2017-07-30T17:19:26.842100+00:00 app[web.1]: [2017-07-30 17:19:26 +0000] [10] [INFO] Worker exiting (pid: 10)
2017-07-30T17:19:26.852227+00:00 app[web.1]: [2017-07-30 17:19:26 +0000] [4] [INFO] Handling signal: term
2017-07-30T17:19:26.868822+00:00 app[web.1]: [2017-07-30 17:19:26 +0000] [4] [INFO] Shutting down: Master
2017-07-30T17:19:27.014793+00:00 heroku[web.1]: Process exited with status 0
2017-07-30T17:19:30.765424+00:00 heroku[web.1]: Starting process …